Japanese Laid-open Patent Publication No. 2007-268164 and Japanese Laid-open Patent Publication No. 2011-90702, for example, discuss techniques for detecting the state of a person operating a computer or driving a vehicle based on detecting a line of sight of the person from an image photographed by a camera and using the motions of the detected line of sight. A camera used for detecting the line of sight in these techniques may be disposed in a fixed manner to the computer or the vehicle.
However, since a tablet terminal or a smartphone including a camera function is operated while being held by a person, the photographed image may be blurry due to camera shake and the like thus making the detection of the line of sight from the photographed image difficult. One aspect of the present disclosure is to detect the line of sight of a person with high precision.